1. Field of the Invention
The present invention is related to the field of erosion control and, more particularly, to a soil erosion control mat having interlocking panels that is suitable for placement in a flow of water where the mat absorbs the impact of wave action, turbulence and flow-induced shear stress while acting to prevent horizontal shifting and vertical uplifting of underlying soil or other erosion control materials.
2. Description of the Related Art
Soil erosion is a problem in areas subject to high impact water flow such as shorelines, streambanks, levees, dam facings, spillways, culvert outlets, channels and chutes. Erosion protection in these areas often entails the use of hard armor materials such as rock riprap, poured concrete or articulating concrete blocks. U.S. Pat. No. 6,951,438 (“the '438 patent”) discloses a lightweight erosion control transition mat provided with a riser, a plurality of voids and a smooth bottom. The mat includes a hard armor erosion control surface and soft armor erosion control material adjacent thereto. The riser and voids act to collect sediment by slowing and diverting effluent from the hard armor surface to reduce scour and impact on the soft armor material. Because of its rigidity and relatively smooth bottom surface, the mat disclosed in the '438 patent is unable to closely conform with the underlying soil surface and must be held in place by fasteners secured in the soil to prevent migration of the mat. The mat of the '438 patent is also incapable of interacting with, confining and preventing horizontal shifting of underlying materials.
U.S. Pat. No. 4,002,034 discloses a non-woven fiber medium having openings in the top surface and a top cover sheet with pressure reactive flaps that close during wave run-up to prevent erosion while allowing for the release of hydraulic pressure from beneath the soil. There is no provision, however, for wave subsidence and the holes in the mat do not form substantial columns within the mat for sediment collection and significant interaction with and reinforcement of surrounding vegetation.
Permanent rolled erosion control products such as turf reinforcement mats (TRM's), typically made of lightweight, buoyant materials such as polypropylene or polyethylene fibers woven, extruded or stitched into relatively open matrices, may also be used in areas with high impact water flow for immediate erosion protection and permanent vegetation reinforcement. However, due to their lightweight, buoyant and relatively open structure, TRM's are often incapable of resisting the uplifting forces of turbulent concentrated water flows and wave action and of sufficiently preventing movement of soil particles beneath and/or through the structure.
Accordingly, a need exists for an erosion control mat configured for close conformity with and adherence to the underlying surface that is effective in preventing erosion in areas with alternating wave action and/or turbulent water flow.